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• Python convert binary data (str) to match multiple of float32 size

  15 avril 2016, par Kendall Weihe

  I’m working on a tensorflow project, and I’m working with raw data from a mp3 file. I’m using FFMPEG and capturing STDOUT. FFMPEG outputs binary data in type str but it doesn’t capture the data in a multiple of the size of a float32 ...or apparently that’s what I am assuming from the error I get from the following code...

  import subprocess as sp
  
  command = ["ffmpeg",
  
          '-i', image_file,
  
          '-f', 's16le',
  
          '-acodec', 'pcm_s16le',
  
          '-ar', '44100', # ouput will have 44100 Hz
  
          '-ac', '2', # stereo (set to '1' for mono)
  
          '-']
  
  pipe = sp.Popen(command, stdout=sp.PIPE, stderr=sp.STDOUT, stdin=sp.PIPE)
  
  raw_audio, _  = pipe.communicate(str(88200*4).encode())
  
  audio_array = np.fromstring(raw_audio, dtype="float32") //ERROR
  
  
  
  dataset = np.append(dataset,audio_array)

  Error

  File "main.py", line 68, in maybe_pickle
  
    audio_array = np.fromstring(raw_audio, dtype="float32")
  
  ValueError: string size must be a multiple of element size

  raw_audio is in the form :

  ...7k\x01t\xf9\xc3\x01\xe3\xfa\x11\x02\xfb\xfb~\xff\x90\xfb\xbb\xfc\x83\xfa\xb4\xfd\xde\xfb\xab\xff\x01\xff\xd4\xfe:\x00T\xfd\xe0\xff\xae\xfdV\x01\xd8\xfd\x1a\x04\x0f\xfcR\x05,\xfaG\x05\xb1\xfaD\x05\xa1\xfdP\x04e\x00\xbc\x01\xe6\x00\xdf\xfe`\x00\x16\xfd\xae\x00\xec\xfc\xb7\x00\x7f\...

  Is there a way I can truncate the data ? Or maybe capture the string in an entirely different way ?

• Revision 6c280c2299 : Adjust style to match Google Coding Style a little more closely. Most of these

  1er novembre 2012, par Ronald S. Bultje

  Changed Paths : Modify /vp8/common/arm/arm_systemdependent.c Modify /vp8/common/debugmodes.c Modify /vp8/common/entropymode.c Modify /vp8/common/entropymode.h Modify /vp8/common/extend.c Modify /vp8/common/extend.h Modify /vp8/common/filter.c (...)

• mismatching process id from process execution. Why do they not match and how to fix script to get the correct pid ?

  26 février 2013, par buggedcom

  I'm running a script that executes ffmpeg and outputs stout to a temp file. Along side the output from ffmpeg I'm sending two tokens. one a marker for a failed execution. The other for marking when ffmpeg is completed. I'm trying to output the process id back to the executing script (which is php) however the process id being returned is not that of ffmpeg, rather the bash script.

  The script is as below.

  ((/opt/local/bin/ffmpeg -i '/Users/ollie/Sites/@Projects/PHPVideoToolkit/v2/git/examples/media/BigBuckBunny_320x180.mp4' -y -t '20' -strict 'experimental' -s '142x80' -aspect '16:9' -b:v '10000k' '/Users/ollie/Sites/@Projects/PHPVideoToolkit/v2/git/examples/output/test-1361797899.mp4' && echo '') || echo '' '') 2>&1 > '/Users/ollie/Sites/@Projects/PHPVideoToolkit/v2/git/examples/tmp/phpvideotoolkit_GmxT4T' 2>&1 & echo $!

  Example output from the script is as follows :

  [19] 19316

  However querying ps. The process id of ffmpeg is different. For example :

  Olivers-Mac-Pro:~ ollie$ ps
  
    PID TTY           TIME CMD
  
  19025 ttys002    0:00.00 -bash
  
  19026 ttys002    0:00.00 -bash
  
  19316 ttys002    0:00.00 -bash
  
  19317 ttys002    0:00.00 -bash
  
  19318 ttys002    0:46.56 /opt/local/bin/ffmpeg -i /Users/ollie/Sites/@Projects/PHPVideoToolkit/v2/git/examples/media/BigBuckBunny_320x180.mp4 -y -strict experimental -s 142x80 -aspect 16:9 -b:v 10000k /Users
  
    849 ttys003    0:00.12 -bash
  
   7558 ttys004    0:00.03 -bash

  You see that the process id returned by the script does not match the ffmpeg process id given by ps. Why is this and how can I ammend the original script to get the correct process id ?